1. Field of the Invention
The present invention generally relates to local oscillator (LO) leakage signal reduction. More specifically, the present invention provides independent baseband compensation for a direct LO coupling component and a baseband DC offset component of a LO leakage signal within a transmitter output signal.
2. Background Art
Generally, a wireless radio frequency (RF) transmitter includes a baseband section and an RF section. Baseband information signals are generated and manipulated within the baseband section. The baseband information signals are up-converted and further manipulated within the RF section to produce a transmitter output signal.
Random device mismatches within the constituent components of the baseband section can produce DC offsets within the baseband information signals. These baseband DC offsets can be up-converted by the transmitter to produce a LO leakage signal. Undesired direct coupling of LO signals to the RF section can also produce or enhance a LO leakage signal. The LO leakage signal is an undesirable signal that can interfere with the subsequent detection and demodulation of the transmitter output signal.
The quality of the transmitter output signal suffers if a transmitter fails to compensate for both the direct LO coupling component and the baseband DC offset component of a LO leakage signal. Techniques to reduce a power of the LO leakage signal often estimate and compensate for the direct LO coupling component and the baseband DC offset component simultaneously. Such techniques are expensive in terms of required processing power and required additional components.